CSF dynamics in long-standing overt ventriculomegaly in adults

OBJECTIVE Long-standing overt ventriculomegaly in adults (LOVA) is a form of chronic hydrocephalus and its patho-physiology and treatment remain debated. An analysis of CSF dynamics in this condition has rarely been reported. The aim of this study was to analyze hydrodynamic characteristics of patients with suspected LOVA to discuss its pathophysi-ological mechanisms and the importance of CSF dynamics analysis for diagnosis and treatment of these patients.METHODS This retrospective cohort study, conducted between May 2018 and October2022, included adult patients aged > 18 years investigated in a department of neurosurgery through a lumbar infusion study for suspicion of LOVA (n = 23). These patients were then compared with a control cohort explored for suspicion of idiopathic normal pressure hydrocephalus (iNPH; n = 30). Clinical symptoms, radiological findings, and hydrodynamic parameters were analyzed. The authors specifically compared two hydrodynamic parameters: resistance to CSF outflow, or Rout, which relies on CSF resorption, and pressure-volume index (PVI), which reflect overall craniospinal compliance. The lumbar infusion study was considered pathological (confirming the diagnosis of chronic hydrocephalus) when at least one of these two parameters was altered.RESULTS Rout was significantly less frequently increased (cutoff >= 12 mm Hg/ml/min) in patients with LOVA (52%) than in those with iNPH (97%; p < 0.001). In contrast, PVI was impaired (cutoff <= 25 ml) in both cohorts, i.e., in 61% of patients with LOVA and in 83% of patients with iNPH. Overall, the rate of pathological lumbar infusion study in LOVA (87%) was not statistically different than in iNPH (100%). However, PVI was the only impaired parameter most frequently found in those with LOVA (35%) compared with those with iNPH (3%; p = 0.002).CONCLUSIONS This study suggests that there is a differential CSF dynamics pattern when comparing patients with LOVA versus those with iNPH. A higher proportion of patients with LOVA showed isolated compliance impairment. These findings highlight the utility of CSF dynamics analysis for the evaluation of patients with suspected chronic ob-structive hydrocephalus such as LOVA. Future research with larger case series may help define diagnosis and treatment algorithms of chronic obstructive hydrocephalus based on CSF dynamics analysis, in addition to clinical and radiological criteria.

Automated summary

This study found a differential cerebrospinal fluid (CSF) dynamics pattern between patients with Long-standing Overt Ventriculomegaly in Adults (LOVA) and those with idiopathic normal pressure hydrocephalus (iNPH). A higher proportion of LOVA patients showed isolated compliance impairment. Therefore, CSF dynamics analysis plays a significant role in evaluating LOVA patients, and future research may help define diagnosis and treatment algorithms for LOVA based on CSF dynamics analysis.